TECTONIC SUMMARYThe December 7, 2012 M 7.3 earthquake east of Sendai, Japan, occurred as a result ofreverse faulting within the oceanic lithosphere of the Pacific plate, approximately 20 kmeast of the plate boundary between the Pacific and North America plates that marks thelocation where the Pacific subducts beneath Japan. At the epicenter of this earthquake,the Pacific plate moves west-northwestard with respect to the North America plate at avelocity of approximately 83 mm/yr. Note that some authors divide this region into severalmicroplates that together define the relative motions between the larger Pacific, NorthAmerica and Eurasia plates; these include the Okhotsk and Amur microplates that arerespectively part of North America and Eurasia.The plate boundary region surrounding the December 7, 2012 earthquake hostsmoderate to large earthquakes fairly regularly – 12 events of M7 or larger have occurredwithin 250 km of this earthquake over the past 40 years. These historic events includethe M9.0 Tohoku earthquake of March 11, 2011, which ruptured a large portion of thesubduction zone plate interface to the west of the December 7th event, and whichspawned a major tsunami that caused significant devastation along the Honshu coast. Aseries of aftershocks of that 2011 megathrust event also occurred to the east of the plateboundary within the Pacific plate, including a M 7.6 normal faulting earthquake 60 km tothe northeast of the December 7 2012 event.

_̂

Map prepared by U.S. Geological SurveyNational Earthquake Information Center10 December 2012Map not approved for release by Director USGS

EARTHQUAKE SUMMARY MAP XXXU.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

##

##

#

#

#

#

#

#

#

#

#

#

#

#

##

##

##

##

##

##

##

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

##

#

#

#

##

##

##

##

##

##

##

#

#

#

#

##

##

##

##

##

##

##

##

##

##

#

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(!(!(

!(

!(

!(!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!( !(!(

!(

!(

!(

!(!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(!(

!(!(

!( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !(

!(

!(

!(!(

!(

!(

!(

!(!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!

!

!!

!

!

!

!

!

!

!

!

_̂

2011

2011

2003

2003

2005

2005

2008

20112011

2011

2011

Sagamihara

Saitama

TokyoHachioji Funabashi

Shizuoka-shi

Yokohama-shi

Sendai-shi

Chiba-shi

Niigata-shi

146°

146°

144°

144°

142°

142°

140°

140°

40° 40°

38° 38°

36° 36°

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(!(!(!( !(!(

!(!(

!(

!(

!(

!(

!(!(

!(!(!(

!(!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(!(

!(!(

!(!(

!(!(

!(!(!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(!(!(!(

!(

!(

!(

!(

!(

!(!(!(

!(!(!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(!(

!(

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(!(!(

!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(!(!(

!(!(!(

!( !(!(!(

!(!(!(!(!(

!(

!(

!(

!(

!(!(

!(

!(

!(

!(!(!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !(

!(

!(

!(!(

!(

!(

!(

!(

!(

!(

!

!

!

!

!

!

!

!

!

!!

!

!

!

!

!

!

_̂

HamamatsuKyoto

Matsuyama

Nagoya

Niigata

Okayama Osaka

Sapporo

Sendai

Shizuoka

TokyoYokohama

150°

150°

140°

140°

40° 40°

M7.3 Offshore Eastern Japan Earthquake of 07 December 2012

0 300100 200Kilometers

##

#

#

#

##

##

##

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

##

##

##

##

##

##

##

#

#

#

#

#

#

#

#

#

#

#

#

#

!

!

!

!

!

!

!

!

!

!!

!

!

!

!

!

!

_̂

HamamatsuHiroshima

Kyoto

Matsuyama

Nagoya

Niigata

Okayama Osaka

Sendai

Shizuoka

TokyoYokohama

150°

150°

140°

140°

40° 40°

0 250 500 750125Kilometers

Scale

Prepared in cooperation

with the Global Seismographic

Network

Tectonic Setting

Seismic Hazard

Epicentral Region

Seismic hazard is expressed aspeak ground acceleration (PGA)on firm rock, in meters/sec²,expected to be exceeded in a50-yr period with a probability of

EXPLANATION_̂ Main Shock

Earthquake Depth!( 0 - 69 km!( 69 - 299 km!( > 299 km

# SubductionTransformDivergentOthers

0 500 1,000 1,500250Kilometers

Scale

1:3,000,000Scale

Significant Earthquakes Mag >= 7.5Year Mon Day Time Lat Long Dep Mag1915 11 01 0724 38.300 142.900 35 7.51923 09 01 0258 35.405 139.084 35 7.91923 09 02 0246 34.900 140.200 35 7.61933 03 02 1731 39.224 144.622 35 8.41938 05 23 0718 36.458 141.755 35 7.71938 11 05 0843 37.009 142.045 35 7.91938 11 05 1050 37.108 142.081 35 7.81938 11 06 0853 37.287 142.283 35 7.7

1960 03 20 1707 39.871 143.435 2.1 7.81964 06 16 0401 38.434 139.226 13.1 7.51978 06 12 0814 38.224 142.009 53.3 7.72011 03 09 0245 38.435 142.842 32 7.52011 03 11 0546 38.297 142.373 29 9.12011 03 11 0615 36.271 141.107 48 7.92011 03 11 0625 38.058 144.590 18 7.7

Peak Ground Acceleration in m/sec**2

.2 .4 .8 1.6 2.4 3.2 4.0 4.8

EPICENTRAL REGION

EXPLANATION_̂ Main Shock

EarthquakesDepth!( 0 - 69 km!( 69 - 299 km!( > 299 km

# SubductionTransformDivergentOthers

1:9,000,000

1:9,000,000

EPICENTRAL REGION

M 5.6 Offshore Eastern Japan Earthquake 07 December 2012 08:18:2437.889°N, 144.090°WDepth 36.1 kmMw = 7.3 (USGS)

PAGER

Did You Feel It?

REFERENCESBird, P., 2003, An updated digital model of plate boundaries: Geochem. Geophys. Geosyst., v. 4, no. 3, pp. 1027- 80.Engdahl, E.R. and Villaseñor, A., 2002, Global Seismicity: 1900 - 1999, chap. 41 of Lee, W.H.K., and others,eds., International Earthquake and Engineering Seismology, Part A: New York, N.Y., Elsevier Academeic Press, 932 p.Engdahl, E.R., Van der Hilst, R.D., and Buland, R.P., 1998, Global teleseismic earthquake relocation with improved trav- el times and procedures for depth determination: Bull. Seism. Soc. Amer., v. 88, p. 722-743.

DATA SOURCESEARTHQUAKES AND SEISMIC HAZARD USGS, National Earthquake Information Center NOAA, National Geophysical Data Center IASPEI, Centennial Catalog (1900 - 1999) and extensions (Engdahl and Villaseñor, 2002) HDF (unpublished earthquake catalog) (Engdahl, 2003) Global Seismic Hazard Assessment ProgramPLATE TECTONICS AND FAULT MODEL PB2002 (Bird, 2003) Ji, C., D.J. Wald, and D.V. Helmberger, Source description of the 1999 Hector Mine, California earthquake; Part I: Wavelet domain inversion theory and resolution analysis, Bull. Seism. Soc. Am., Vol 92, No. 4. pp. 1192-1207, 2002. DeMets, C., Gordon, R.G., Argus, D.F., 2010. Geologically current plate motions, Geophys. J. Int. 181, 1-80. BASE MAP NIMA and ESRI, Digital Chart of the World USGS, EROS Data Center NOAA GEBCO and GLOBE Elevation Models

DISCLAIMERBase map data, such as place names and politicalboundaries, are the best available but may not be current or may contain inaccuracies and thereforeshould not be regarded as having official significance.

ShakeMap